From Longman Dictionary of Contemporary Englishfeldsparfeld‧spar /ˈfeldspɑː $ -ɑːr/ noun [uncountable] HEGa type of grey or white mineral
Examples from the Corpus
feldspar• Electron microprobe element maps show the distribution and quantity of alkali feldspar in the fine-grained groundmass of the altered basalts.• Ankerite, haematite, mica and feldspar have also been identified in smaller quantities.• Petrological observations show excess feldspar in many basaltic lavas which is most easily explained by crystal settling.• If feldspar is present, it is in minor volumes or traces.• Finally, a temperature is reached when a third mineral, feldspar, joins in.• Quartz, feldspar, and the clay minerals make up the bulk of that contribution.• They contain large amounts of the feldspar mineral.Origin feldspar (1700-1800) German feldspath, from feld “field” + spath type of mineral 